Mobile banking is the fastest growing way consumers access their account, with the number of customers using a mobile banking app doubling over the past year.

These apps offer all of the basic banking services including the ability to check your balance and transactions, make payments or find the nearest branch or ATM. How should banks ensure that these apps add value and are seen by their customers as more than just glorified spreadsheets?

Banks are beginning to innovate by adding extra features to their apps. Barclays offers a secure storage facility for your documents by uploading pictures to the app. Santander enables you to report your card as lost or stolen. Halifax offers its ‘Homefinder’ app which, alongside a mortgage calculator, uses data from zoopla to provide details of local house prices. You can even hold your phone up and the app will add on information about the homes you can see.

But some banks are asking why they should restrict their offering of apps to only the bank’s ideas. Instead they use the imagination of their customers and outside developers.

In a great example of open innovation, Credit Agricole, France’s largest retail bank has thrown open its service to outside developers. It published details of its interface, which contains the detail of how individual customer information is identified – enabling the developers to write code which interacts with this data.

The bank launched the CA app store, which gives these third-party apps space to be promoted to its customers. It also allows customers to suggest ideas for Apps which they want to see developed and allows developers to interact with them. Finally, it allows developers to suggest data which should be released by the bank.

“Applications designed by a banker look like what a banker can imagine…We needed to have the customer’s point of view to … make us think about another way of creating applications to meet customer needs.” – Bernard Larriviere, Director of Innovation, Credit Agricole.

The app store now has 44 apps including a variety of budgeting apps, with the most popular being one aimed at managing your healthcare expenditure and the amount which you will be reimbursed by the French health insurance system. There are also apps to help you reach your savings goals, and make an insurance claim by giving details of a car accident – using your smartphone to take pictures. Apps are also available which enable the customisation of how your banking information is displayed, either to give it a more futuristic feel or to help people with visual impairments see it clearly.

Security is vital and Credit Agricole stresses that no outside developer actually has access to any individual customer details. They also check the apps in the store to make sure they contain no malware or other harmful viruses.

Spanish bank BBVA took a different approach by opening up its transaction data to developers. Its “Innova Challenge” made data available concerning transactions in Madrid and Barcelona. This data included the time when the purchases were made, the demographics of customers including their age and gender and the category of the spending – for example spending in bars and restaurants, hotels and supermarkets and on travel, leisure, food and technology.

The winners in the consumer category included Qkly – an app which uses the data to predict the time of day when waiting times at shops and attractions would be the longest and Mad4food which recommends restaurants and neighbourhoods based on data where similar people like to go. In the business category, winners included two apps aimed at helping decide the best places to establish small businesses.

Mobile banking is an increasingly important factor for people when choosing a bank account – particularly among younger consumers. Those banks that can harness the power of imagination to develop cutting edge banking apps will find it easier to surprise, delight and retain their customers.